# 设计相关质数计算

# 判断一个数是否为质数
def if_zhishu(num):
    n = 2
    while n * n <= num:
        if num % n == 0:
            return False
        n += 1
    return True


prime_num_list = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101,
                  103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199,
                  211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317,
                  331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443,
                  449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547]


# 获取第n个质数,n从0开始，若n小于100直接返回prime_num_list【n】，若n超过100则扩展列表，直到能直接返回prime_num_list【n】
def get_prime_num(n):
    while n > len(prime_num_list):
        l = list()
        for i in range(prime_num_list[-1] + 1, prime_num_list[-1] + 1000):
            if if_zhishu(i):
                l.append(i)
        prime_num_list.extend(l)
    return prime_num_list[n]


# print(get_prime_num(50))
# print(len(prime_num_list))
# print(get_prime_num(200))
# print(len(prime_num_list))
# print(get_prime_num(300))
# print(len(prime_num_list))

